In recent years, discharge means of micro liquid droplets is used as production means of products or the like in any field. The micro liquid droplet discharge means is used as, for example, ink discharge means in a printing apparatus; means for discharging and dispensing a predetermined liquid in a field of medical treatment, manufacturing organs of living body, drugs, food or the like; and means for forming an electrode film in a manufacturing process of a fuel cell or an electronic component. Especially in a blood analysis unit in the medical field, a genetic inspection unit or an inspection unit for new drug inspection or the like, for running cost reduction or throughput improvement, miniaturization is demanded to change the existing minimum discharge amount (dispensing amount) of a microliter (μl) order to that of a nanoliter (nl) order, and liquid droplet discharge means is required which is capable of stably discharging the droplets as much as the discharge amount of the nl order with good reproducibility. In a unit for forming the electrode film, means capable of discharging the liquid droplets of the nl order in a non-contact manner is expected in order to stably form a film having a uniform thickness.
To meet such a demand, for example, in Patent Document 1, an ink jet head which deposits ink liquid droplets onto an image recording medium is disclosed. The disclosed ink jet head is an ink jet head composed by bonding, to a substrate in which an ink jet port is formed, a piezoelectric element block formed by laminating a plurality of plate-like piezoelectric materials via a conductive material, and having hollowed portions composing a pressure chamber; and then bonding, to the piezoelectric element block, a lid in which an ink supply port is formed, and changes a volume of the pressure chamber by displacements of piezoelectric elements composing the piezoelectric element block.
Moreover, in Patent Document 2, there is proposed a metal liquid jet unit equipped with a liquid filling portion; a liquid injection port; a liquid jet port to jet the liquid; and a bimorph or unimorph type piezoelectric element to drive and jet the liquid, and channels are formed in series on the piezoelectric element.
Furthermore, in Patent Document 3, means for imparting an inertial force to the liquid to discharge the liquid is proposed. A disclosed liquid dispensing unit is a unit having a liquid holding member (a container which holds a discharge nozzle and a solution); and driving means (a piezoelectric element) for moving the liquid holding member, and the unit moves the liquid holding member with the driving means (accelerates the discharge nozzle to thereby impart the inertial force to the liquid), thereby discharging the liquid droplets. Furthermore, as another prior document, Patent Document 4 is known.
Patent Document 1: Japanese Patent Application Laid-Open No. 7-81055;
Patent Document 2: Japanese Patent Application Laid-Open No. 2000-6400;
Patent Document 3: Japanese Patent Application Laid-Open No. 2001-235400; and
Patent Document 4: Japanese Patent Application Laid-Open No. 7-40536.